SALEM
SALEM STUDY SYSTEM
EOPs > EOP-LOSC-2 — Uncontrolled Depressurization of All Steam Generators

EOP-LOSC-2 — Uncontrolled Depressurization of All Steam Generators

⚠️ DRAFT

EOP-LOSC-2 — Uncontrolled Depressurization of All Steam Generators

Purpose

Provides operator actions for responding to an uncontrolled depressurization of all steam generators, including restoration of pressurizer heater power.

Key Actions / Information

Exam — 2023 Q7
Step 26 — restore normal power to PZR heaters or transfer to emergency backup. PZR heater Group 1 is normally powered from 2G bus, with emergency backup from 2C 460V vital bus. Group 2 is normally powered from 2E bus, with emergency backup from 2A 460V vital bus. The transfer is manual.
Scenario — 2022 #3
CT#1 (CT-12) requires crew to manually actuate MSLI before a Red path to subcriticality or integrity CFST, or transition to EOP-LOSC-2. Failure to close MSIVs when the main turbine fails to trip causes uncontrolled depressurization of all SGs — the entry condition for LOSC-2. In this scenario, the crew prevents entry to LOSC-2 by using Fast Close pushbuttons on 2CC2.
Exam — 2018 Q66
Step 1 — 13 AFW Pump steam isolation: with 1A 4KV VITAL BUS de-energized (11 AFW Pump lost) AND 12 AFW Pump will NOT start, the 13 AFW Pump (TDAFW) is the ONLY source of AFW flow → steam will NOT be isolated to 13 AFW Pump. Step 5 — AFW flow control: with RCS cooldown rate > 100 °F/HR (120 °F/HR), reduce AFW flow to no less than 1.0E04 LB/HR to each SG. Key trap: 11 AFW is powered from 1A 4KV — must recognize that 1A 4KV loss takes out 11 AFW. If cooldown rate were < 100 °F/HR, the criterion changes to maintaining SG NR levels < 33%.
Exam — 2019 Q66
Step 1 — 13 AFW Pump (TDAFW) steam isolation: if the 13 AFW Pump is NOT the only source of AFW flow (i.e., at least one MDAFW pump is available), steam will be isolated to the 13 AFW Pump. With 1C 4KV Vital Bus lost, 11 MDAFW Pump is NOT available but 12 MDAFW Pump IS — so steam IS isolated to 13 AFP. Step 5 — AFW flow control with RCS cooldown rate > 100 °F/HR: reduce AFW flow to no less than 1.0E04 LB/HR to each SG. If cooldown rate were < 100 °F/HR, the criterion would be to maintain SG NR levels < 33% instead.

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